Pendulum inclinometer



Qct. 13, 1936. c. M. LEM-HERMAN .2,057,335 l PENDULUM INCLINOMETER Filed Nov. 29, 1930 gyn/vanto@ f5 CLARENCE Mlmntmu Patented Qct. 13, 1936 UNITED STATES APn'rslsl'r OFFICE.

PENDULUM INCLIVNOMETER Application November 29, 1930, Serial No. 498,990

6 Claims.

This invention relates to a pendulum inclinometer and especially to such an instrument which will indicate the position of the ship relative to the ground and the horizon, and has for its general object the provision of an instrument which `will increase the safety of flying.

A further object of this invention is to provide an instrument which will indicate to the pilot the vital action of the plane under all possible -10 weather conditions.

A more specific purpose is to provide an inclinometer which will enable the .pilot to see at a glance the relative position of hisV ship to the horizon and the ground. A further object is to f1.5 enable the .pilot to hold the plane in level flight,

parallel with the horizon, and provide a device which will indicate the angle of departure from such condition in degrees.

A further object is the provision of an instru- '20 ment which will indicate to the pilot the degree of the climb as the ship noses up, or the degree of the dive if the ship should nose downward.

Other features of my invention will be explained by reference to the accompanying drawing showring the preferred embodiment thereof and in which,

.. Fig. 1 is a side elevation of the instrument to indicate the `angle of departure from level flight `in degrees;

l5:30` Fig. 2 `is a horizontal section and is indicated 1 by the lines 2-2 in Fig.A 1.

Fig. `3 is a detail vertical section and is indicated by the lines 3 3 in Fig. 2.

My improved device or instrument includes a mechanism which indicates to the pilot'whether or not the ship is flying on an even keel, that is whether or not the nose of the ship is pointed upward or downward relative to the earth. These z several improvements have been gathered tomo fgether to form a composite indicating Ydevice :which may be located immediately in front of the pilot so that he may tell at a glance the flight conditions of his aircraft.

In the drawing the instrument is shown as m being housed in a boxlike casing I0, comprising vvision of the latter.

mounted in the bottom wall I3, and includes a compass 20, whichmay be of any well known type either earth induction or gyroscopic and which has a horizontal dial.

To assist the pilot in holding the ship level in fi5 flight,` parallel with the horizon, and ground I prefer to mount a miniature ship within the casing I 0. As illustrated in the drawing, this miniature ship is indicated at and comprises a fuselage member 8| and suitable wings 82.

extendingrod or shaft 83 carried by the side walls II and" I2 of the casing, .and which lies substantially ,in the center of .a vertical -plane which is located a short distance in front of the compass 15 thereby ,preventing interference with the pllots The miniature ship is so mounted that the axis of the wings thereof lie at all times parallel with the axis ofthe wings of the plane in which the instrument is mounted.; 20

Immediately in front of the miniature ship is a rotatable anged disc 85 which is mounted on a suitable ball-bearing unit 86 carried by a stub shaft 8l. 'I'he shaft 8l is rigidly mounted on a bracket 88 which is secured by suitable bolts 39,` 25

to the base I3 of the casing. The lower portion of lthe disc 85 is weighted as at 90 so that gravity Will tend .to holdthe disc in the same position `relative to the earthregardless of the position 0f the plane. The disc 85 has a web or .face 92 30 .which normally extends upwardly to the center of the circle, and the uppermost edge 93 of which forms a true `horizontal line (relative to the .the Wingsof the airplane are parallel with the horizon, the upper edge 93 of the vweb 92 will be parallel with the axis of the wings of the miniature ship thereby forming an artificial horizon line. However, when the wings of the airplane: 40 are tilted, thereby becoming non-parallel rela- 'tive to the horizon, the edge 93 of the web 92 which forms the artificial horizon line for the miniature ship will be actuated by gravityand tilted vrelative to the axis of theY wings 82 of the45 .miniature ship, thereby indicating to the Apilot the tilt of thewings of the plane.

For lconvenience I find it desirable to show the angleof tilt or departure from the horizon line in degrees. For this purpose that portion of the.' 5o disc adjacent the plane may be marked in degrees. It will now be noted that the artificial horizon line is tilted slightly from the axis of the wings of the miniature ship 80 and from the upper edge of a wall or partition 9| of the casing-'55 The VlO vminiature ship 80 is mounted on a transversely wing is low, one side of the horizon line will immediately show over the top of the miniature ship and will indicate which wing is low and the degree thereof. In banking the plane when making a turn, centrifugal force will counteract the action of gravity on the weighted disc 85A and the artificial horizon line coincide with the axis of the wings of the miniature ship when a perfect bank is made, however when an improper bank is made the centrifugal forcey will either overcome or-will not balance the force of gravity, and the articial horizon will not coincide with the axis of the wings of the miniature ship, and will therefore indicate a slippage, and gives the direction and angle of such slippage. This is due to the fact that the angle of a perfect bank is Athe component of the forces of gravitation and the centrifugal force of the plane, and as the weighted disc 85 is respondent to both of these forces as is the plane itself, any departure from the proper banking of the plane will be a departure from the component of these forces and therefore, will show relative movement between the artificial horizon and the axis of the wings of the miniature ship.

As heretofore mentioned the instrument includes a mechanism which indicates to the pilot, whether or not the airplane is ying on an even keel, that is whether or not the nose of the plane is pointing upward or downward. To accomplish this, I prefer to provide a rotary disc |0| which is located at one side of the casingy |0 and which rotates in a plane at right angles to the plane of rotation of the disc 85 and which plane is parallel to the axis of flight of the airplane. I prefer to connect this rotary disc |0| with the miniature plane in such a manner that when the airplane noses up for a climb the miniature ship 80 will do likewise, also when the plane points downward as in a dive, the miniature ship will do likewise, in fact, the miniature ship will virtually go through the same performance within the casing, or relative to the casing I0 as the large ship does with respect to the earth, and thereby enable the pilot to know at all times the position of his airplane with reference to the earth. I prefer to so actuate this device that no disturbance of the elements can alter this relationship.

The disc |0| is rotatably mounted on a stud |00 which is rigidly secured to the side wall |2 of the casing I0. Rigidly secured to this disc |0| is a gear |02 which meshes with a gear |03 rigid with the shaft 83 which carries the miniature ship. Hence as the disc |0| is rotated it will cause the miniature ship to nose up or down depending upon the directionr of rotation of the disc.

I nd it expedient under average ying conditions to operate the rotary disc by gravity, however I nd that when the plane is brought quickly into a dive or climb, gravity will not act quick enough to show the true angle of such climb or dive, I therefore find it expedient to actuate the rotary disc by a mechanism which is respondent both to gravity and centrifugal force.

As illustrated in Figs. 1 and 2 I mount a lever |05 on a pivot |06 carried by the stud 00. This lever has a relatively short arm |01 which extends downwardly and a comparatively long arm |08 which extends upwardly. Pivotally secured to the arm |01 of the lever |05 is an arm |09 of a T-shaped lever ||0 and an arm I9 of a second T-shaped lever |20. Suitable links |3| and |30 are connected to the levers |20 and ||0 respectively. The links |30 and |3| are in turn connected to a common pivot |50 mounted on a bar |5| which is pivoted at one end to a laterally extending ear |52 of the lever |05 as at |53. The other end of the bar 5| is connected by the link |55v to a"pin |56 located on the disc |0|.

One end of a suitable tension spring |34 is connected to the pivot |50 and the other end secured to an adjusting bolt |35 carried by an outwardly extending portion |35 of the upper arm |00 of the lever |05. A suitable adjusting nut |31 is provided to lock the spring in its adjusted position. 'I'he levers ||0 and |20 are provided with substantially downwardly extending arms |40 and |4| respectively, to which arms are secured suitable weights |43.

When centrifugal force, such as results from the quick upward movement of the plane, acts on the weights |43, they are drawn approximately downwardly, and at the same time vdrawing the pivot |50 downwardly and lengthening the spring |34 whose tenseness will serve to return the parts to their normal position. This acts through the parallelogram, (consisting of the arms |32 and |33 of the levers ||0 and |20, and the links |30 and |3|) and causes the bar |5| to be rocked counter clockwise about its pivot |53. This lcauses the link |55 to rotate the disc |0| and the gear |02 in a counter clockwise direction and the gear |02 rotates the gear |03 and the shaft 83, in a clockwise direction thereby pointing the miniature shipupward, to indicate the actual position of the main plane. It is also of importance to note that the links |30 and |3| are pivoted at point |50 which is far in the rear of the fixed stud |00, as made clear in Fig. 2 of the drawingthese parts |00 and |50 being quite independent in construction and operation.

When gravity acts upon the weights |43, it tends to rock the entire linkage and leverage about the pivot |06 thereby causing the link |55 to impart a rotative movement to the disc |0|. Hence it will be seen that as the plane noses upward both gravity and centrifugal force will tend to rotate the disc |0| and in event of a continued.l

upward movement of the plane gravity will -act on the disc and maintain itin its rotated position. As this disc is geared to the miniature ship it will likewise be rotated thereby indicating to the pilot the position of his ship relative to the the left hand weight moves in counter clockwise' direction, about their respective pivots. The angle between the links |30 and |3| is increased moving their spaced ends and common pivoted connection with the arm |5| downward, thereby moving or swinging the arm |5| counterclock-5 wise about its pivot |53 and moving the disc or rotor |0| in a counterclockwise direction. Likewise centrifugal force acts to align each weight |43 and its pivotal connection to the arm |05, with the pivot about which the arm swings. Such a'move-f of tiltof the plane, and to this end the periphery '75 of the disc I I may be graduated into degrees as indicated at |60 on Fig. 1. The front wall I5 of the casing has an opening IGI through which the periphery disc is visible. Suitable indicating marks provided on the front wall I5, are adapted to coact with the markings I 60 on the disc to indicate to the pilot the angle of tilt ofhis plane. If desired, the opening I6I may be covered by a suitable transparent insert |65.

Having set forth the principles of my invention, and described and illustrated an embodiment thereof for practical use, what I claim and desire to secure by Letters Patent, is-

1. An aeronautical inclinometer comprising a support, a miniature airplane mounted to tilt fore and aft in said support, Weighted means rotatively mounted in said support to form an artificial horizon line associated with said airplane, and to cause a relative angular movement between said articial horizon line and the transverse axis of said miniature airplane, means responsive to the inclination of the craft and connected with said miniature airplane to cause proportional movement of said miniature airplane about its transverse axis, and a rotor associated with said last named means to indicate in degrees such movement with respect to the support.

2. An aeronautical inclinometer comprising a support, a miniature ship mounted to tilt fore and aft in sai-d support, weighted means rotatively mounted in said support to form an artificial horizon line associated With said ship, means actuated by gravity and centrifugal force to move said miniature ship about a transverse axis, and a rotor associated with said actuating means to indicate in degrees such movement with respect to the support.

3. An aeronautical inclinometer comprising a support, a miniature air ship mounted to tilt fore and aft in said support, gravity-actuated means rotatively mounted in said support to form an articial horizon line associated with said air ship and to cause relative rotation between said artificial horizon line and the transverse axis of said miniature air ship, means actuated by gravity and centrifugal force to move said miniature air ship about its transverse axis, said means also being responsive to centrifugal force alone, and a rotor associated with said last named gravity means to indicate in degrees such movement of said miniature air ship about its transverse axis with respect toI the support.

4. An inclinometer comprising a support, an indicator rotatably mounted in said support, a lever rotatable about the axis of the indicator relative to said support, a pair of weighted arms pivotally connected to said lever eccentrically of the axis of said indicator, an arm pivoted to said lever eccentrically of the axes of said indicator and the pivots of said Weighted arms, links connecting said weighted arms to said second named arm, and a connection between said second named arm and said indicator.

5, An inclinometer comprising a support, an indicator rotatably mounted in said support, a lever rotatable about the axis of the indicator relative to said support, a pair of weighted arms pivotally connected to said lever eccentrically of the axis of said indicator, an arm pivoted to said lever eccentrically of the axes of said indicator and the pivots of said weighted arms, links connecting said Weighted arms to said second named arm, and a connection between said second named arm and said indicator, and a resilient means interconnecting said second named arm and said lever to resiliently maintain said weighted arms swung about their respective pivots.

6. An aeronautical inclinometer comprising a support, a miniature ship mounted to tilt fore and aft in said support, weighted means rotatively mounted in sai-d support to form an articial horizon associated with said ship, means responsive to gravity and centrifugal force, to move the miniature ship about a transverse axis, said means being also responsive to gravity acting alone, to move the miniature ship about a transverse axis, and a rotor associated with said actuating means to indicate in degrees, such movement with respect to the support.

CLARENCE M. LEATHERMAN. 

